A multicolor signal light is generally used as a signal indicator in an OEM machine to send a message to an operator. The multicolor signal light is composed of several layers with different colors. Normally the multicolor signal light is controlled by a programmable controller (PLC) in the OEM machine. One layer of the multicolor signal light is controlled by one output control signal of the PLC. As illustrated in FIG. 1, the multicolor signal light 1 controlled by the PLC 2 in the prior art comprises three color layers of red R, yellow Y and green G, for example, and each of the color layers of the multicolor signal light 1 is composed of a plurality of LEDs emitting light with a fixed color. Three control signals PLC_R, PLC_Y, PLC_G and a common ground signal COM are connected between the multicolor signal light 1 and the PLC 2. A control circuit, for example, a processor and the like, included inside the multicolor signal light 1 receives the control signals PLC_R, PLC_Y, PLC_G and controls an emitting of the multicolor signal light 1 according to the control signals PLC_R, PLC_Y, PLC_G. Such structure of the multicolor signal light shown in FIG. 1 is relatively complex, such that a manufacture cost is increased and a process as arranging wires actually is annoying.
In FIG. 1, in order to transfer information, the PLC 2 requires the three control signals PLC_R, PLC_Y, PLC_G so as to control the three color layers of the multicolor signal light 1 to emit light respectively to deliver messages, and each of the color layers is needed to be connected to the corresponding output control signal of the PLC, which results in a high control cost of the multicolor signal light 1.
In a typical application for the multicolor signal light, only one color layer operates during a given period of time in most cases, while remaining color layers would not operate but are wasted.
Therefore, there is needed a multicolor signal light and a control method thereof which has a simple structure, a low cost in control and manufacture, and a simple manufacture process, in order to indicate various message to the operators conveniently.